Ductile prefabricated shear panel

ABSTRACT

A shearwall is disclosed for use in lightweight or other constructions to transmit lateral shear forces and dissipate energy on the construction. In examples, the shearwall includes a central panel formed of wood, and side plates formed of steel. The side plates may be affixed at lower corners of first and second opposed surfaces of the central panel. Each side plate may include a fastening plate for affixing the side plate to the central panel, and a restraint plate which fits within a reduced area section of the central panel between the first and second surfaces.

CLAIM OF PRIORITY

This application is a divisional application of U.S. patent applicationSer. No. 16/400,460, entitled “DUCTILE PREFABRICATED SHEAR PANEL”, filedMay 1, 2019, which application is incorporated herein by reference inits entirety.

BACKGROUND

Shearwalls were developed to counteract the potentially devastatingeffects of natural phenomena such as seismic activity, high winds,floods and snow loads on the structural integrity of light-framedconstructions. Prior to shearwalls and lateral bracing systems, lateralforces generated during these natural phenomena often caused the topportion of a wall to move laterally with respect to the bottom portionof the wall, which movement could result in structural failure of thewall and, in some instances, collapse of the building.

Shearwalls within wall sections of light-framed constructions providelateral stability and allow the lateral forces in the wall sections tobe transmitted through the shearwalls between the upper portions of thewall and the floor diaphragm or foundation of the building where theyare dissipated without structural effect on the wall or building. Whilevarious shearwall designs are known, there is a constant demand forimproved shearwalls providing greater structural performance relating tostrength, stiffness, ductility and energy dissipation.

SUMMARY

The present technology relates to a shearwall for use in lightweight orother constructions to transmit lateral shear forces and dissipateenergy on the construction. In examples, the shearwall includes acentral panel formed of wood, and side plates formed of steel. The sideplates may be affixed at lower corners of first and second opposedsurfaces of the central panel. Each side plate may include a fasteningplate for affixing the side plate to the central panel, and a restraintplate which fits within a reduced area section of the central panelbetween the first and second surfaces. The reduced area section providesa predictable and controllable location of yielding of the shearwall.The restraint plates add ductility to the shearwall after initialfailure, by bearing against the central panel after initial yield at thereduced area section.

This Summary is provided to introduce a selection of concepts in asimplified form that are further described below in the DetailedDescription. This Summary is not intended to identify key features oressential features of the claimed subject matter, nor is it intended tobe used as an aid in determining the scope of the claimed subjectmatter. The claimed subject matter is not limited to implementationsthat solve any or all disadvantages noted in the Background.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a shearwall according to embodiments ofthe present technology.

FIG. 2 is a front view of a shearwall according to embodiments of thepresent technology.

FIG. 3 is a rear view of a shearwall according to embodiments of thepresent technology.

FIG. 4 is an edge view of a shearwall according to embodiments of thepresent technology.

FIG. 5 is an exploded perspective view of a shearwall according toembodiments of the present technology with the side plate assembliesseparated from the central panel.

FIG. 6 is an enlarged perspective view of a lower corner of the centralpanel according to embodiments of the present technology.

FIG. 7 is a further enlarged perspective view of a lower corner of thecentral panel according to embodiments of the present technology.

FIG. 8 is a front view of a first side plate assembly according toembodiments of the present technology.

FIG. 9 is a rear view of a first side plate assembly according toembodiments of the present technology.

FIG. 10 is an edge view of a first side plate assembly according toembodiments of the present technology.

FIG. 11 is an exploded perspective view of a first side plate assemblyshowing the restraint plate being affixed to the fastening plateaccording to embodiments of the present technology.

FIG. 12 is a front view of a first restraint plate according toembodiments of the present technology.

FIG. 13 is a front view of a second side plate assembly according toembodiments of the present technology.

FIG. 14 is a rear view of a second side plate assembly according toembodiments of the present technology.

FIG. 15 is an edge view of a second side plate assembly according toembodiments of the present technology.

FIG. 16 is an exploded perspective view of a second side plate assemblyshowing the restraint plate being affixed to the fastening plateaccording to embodiments of the present technology.

FIG. 17 is a front view of a second restraint plate according toembodiments of the present technology.

FIG. 18 is a perspective view showing a lower corner of a shearwallincluding a structural fuse according to embodiments of the presenttechnology.

FIG. 19 is an edge view showing a lower corner of a shearwall includinga structural fuse according to embodiments of the present technology.

FIG. 20 is an exploded perspective view showing an anchor bolt andbearing washer plate for affixing the corners of the shearwall 100 to afoundation.

FIG. 21 is a front view of a bearing washer plate according toembodiments of the present technology.

FIG. 22 is a front view of an anchor bolt and bearing washer plateaffixing a corner of the shearwall 100 to a foundation.

FIG. 23 is a perspective view of a bottom plate affixed to the bottom ofa shearwall according to embodiments of the present technology.

FIG. 24 is a front view of a bottom plate affixed to the bottom of ashearwall according to embodiments of the present technology.

FIG. 25 is a top view of a bottom plate affixed to the bottom of ashearwall according to embodiments of the present technology.

FIG. 26 is an edge view of a bottom corner of a shearwall buckling orfracturing under compressive or tensile loads above threshold levels.

FIG. 27 is an edge view of a bottom corner of a shearwall with restraintplates bearing on recessed surfaces of the shearwall.

FIGS. 28-30 are exploded perspective, front and edge views of a topplate for affixing a top of the shearwall to an upper support surfaceaccording to embodiments of the present technology.

FIGS. 31-32 are front and rear perspective views of a shearwallaccording to an alternative embodiment of the present technology.

DETAILED DESCRIPTION

The present technology, roughly described, relates to a shearwall havinga high degree of stiffness, strength and ductility for transmittinglateral forces and dissipating energy within a light-frame or otherconstruction. The shearwall includes a central panel and side plates atthe lower corners of front and rear surfaces of the central panel. Theside plates may be affixed to the central panel as by nails, screwsand/or structural bonding, and are used to secure the central panel to afoundation or other support surface for the construction. In particular,a pair of anchor bolts may be provided up through a bottom surface ofshearwall and into openings formed in respective pairs of side plates.Bearing plate washers may then be provided in the openings, over theanchor bolts and supported on the side plates. Hex nuts may then be usedto secure the anchor bolts to the bearing plate washers. By tighteningthe hex nuts, the plurality of side plates may be engaged to removeslack from the shearwall as explained below.

The side plates may each include a fastening plate and a restraint platewelded or structurally bonded onto or otherwise formed on the fasteningplate. The side plates may be mounted in recessed sections formed in thecentral panel, at the lower corners of the front and rear surfaces ofthe central panel. Each recessed section may include a first recess forreceiving the fastening plate, and a second, deeper recess for receivingthe restraint plate. The deeper recesses formed in the front and rearsurfaces of the central panel together define a section of the centralpanel having a narrower width, extending to edges of the central panel.This narrow width section at the edges of the central panel defines astructural fuse element in the shearwall as explained below.

The central panel and side plates provide a high degree of stiffness andstrength to the shearwall to transmit lateral shear forces on theshearwall down into the foundation. When the imposed lateral forcestransmitted to the shearwall result in internal stresses that exceed thecompressive buckling or tensile fracture capacity of the fuse element,the structural fuse will fail at a defined and controllable location.Upon such buckling or fracture at the fuse elements, the pair ofrestraint plates serve to maintain the structural integrity of theshearwall at fuse element locations, and add a high degree of ductilityand energy dissipation to the shearwall after initial fracture due tobearing against the shoulder of the central panel.

It is understood that the present invention may be embodied in manydifferent forms and should not be construed as being limited to theembodiments set forth herein. Rather, these embodiments are provided sothat this disclosure will be thorough and complete and will fully conveythe invention to those skilled in the art. Indeed, the invention isintended to cover alternatives, modifications and equivalents of theseembodiments, which are included within the scope and spirit of theinvention as defined by the appended claims. Furthermore, in thefollowing detailed description of the present invention, numerousspecific details are set forth in order to provide a thoroughunderstanding of the present invention. However, it will be clear tothose of ordinary skill in the art that the present invention may bepracticed without such specific details.

The terms “top” and “bottom,” “upper” and “lower” and “vertical” and“horizontal” as may be used herein are by way of example andillustrative purposes only, and are not meant to limit the descriptionof the invention inasmuch as the referenced item can be exchanged inposition and orientation. Also, as used herein, the terms“substantially” and/or “about” mean that the specified dimension orparameter may be varied within an acceptable manufacturing tolerance fora given application. In one embodiment, the acceptable manufacturingtolerance is ±2.5% of a stated dimension.

FIGS. 1-4 illustrate perspective, front, rear and edge views,respectively, of a shearwall 100 according to embodiments of the presenttechnology. The shearwall 100 includes a central panel 102, four sideplate assemblies 104, 106, 108 and 110, and a bottom plate 112. Thecentral panel 102 may be formed of a material having high strength andstiffness such as for example natural and/or engineered wood. Examplesof engineered wood that may be used in panel 102 include but are notlimited to glulam or structural composite lumber, such as crosslaminated timber, laminated veneer lumber, laminated strand lumber, andparallel strand lumber. The central panel 102 may be formed of othermaterials in further embodiments including for example various metals,plastics, composites and/or polymers.

The central panel 102 may in general be a planar member including afirst, or front, planar surface 116, and a second, or rear, planarsurface 118 opposed to the front surface 116. Edges 120, 122 may extendthe length of the shearwall 100, between the front and rear surfaces116, 118. The central panel 102 may further include a bottom edge 124and a top edge 126. The length, width and thickness of the central panel102 may vary, depending for example on the construction within which itis used, but in one embodiment, the central panel 102 may be 93 incheslong, 24 inches wide and 3 7/16 inches thick. These dimensions may varyproportionately or disproportionately with respect to each other.

As shown for example in FIGS. 1 and 2, the central panel 102 may includea chase 128 for receiving wires, cables and the like, and apertures 130for receiving electrical or structural components, boxes and the like.While chase 128 is shown in the front planar surface 116, the chase 128may additionally or alternatively be provided in the rear planar surface118 in further embodiments. Additionally, the positioning of the chase128 and the apertures 130 are shown by way of example only, and may bein other positions in the central panel 102 in further embodiments.

FIG. 5 is an exploded perspective view of shearwall 100 illustratingthat side plate assemblies 104, 106, 108 and 110 fit within respectiverecessed sections 134, 136, 138 and 140 formed in the front and rearplanar surfaces 116, 118 of central panel 102. The recessed sections134, 136, 138 and 140 may be formed, as by routing, at sides of thefront and rear planar surfaces 116, 118, adjacent edges 120 and 122,near a bottom of the shearwall 100. The recessed sections 134 and 136may be aligned with each other in the front and rear planar surfaces116, 118 adjacent edge 120. The recessed sections 138 and 140 may bealigned with each other in the front and rear planar surfaces 116, 118adjacent edge 122.

FIG. 6 shows greater detail of recessed sections 138 and 140 at thelower corners of the front and rear planar surfaces 116, 118. Recessedsection 138 includes a first recess 138 a formed to a first depth intosurface 116, and a second recess 138 b formed to a second, deeper depthinto surface 116. In embodiments, the first recess 138 a may generallybe rectangular, extending to edge 122 and having a width of 7¼ inches.The first recess 138 a may have a length of 29¼ inches and may start 1inch from the bottom of the central panel 102. In embodiments, the firstrecess may have a depth of 7/32 of an inch. The recess 140 a of recessedsection 140 may have the same position and dimensions. It is understoodthat each of these dimensions is set forth by way of example, and eachmay vary proportionately or disproportionately with respect to eachother in further embodiments.

FIG. 7 shows greater detail of the second recess 138 b at the lowercorner of the front planar surface 116. In embodiments, the secondrecess 138 b may generally be rectangular, extending to edge 122 andhaving a width of 4⅞ inches. The second recess 138 b may have a lengthof 7⅜ inches and may be spaced 3⅛ inches from the bottom of the centralpanel 102 to a height of a shoulder 137. In embodiments, the secondrecess 138 b may have a depth of ½ inch relative to the first recess 138a (or 23/32 of an inch from the planar surface 116). The recess 140 b ofrecessed section 140 may have the same position and dimensions. It isunderstood that each of these dimensions is set forth by way of example,and each may vary proportionately or disproportionately with respect toeach other in further embodiments.

The recesses 138 b and 140 b may have a bottom edge defined by a firstelevation including a shoulder 137, and a second, lower elevationincluding a detent 135, adjacent the shoulder 137. The detent may, forexample, extend ¼ to ½ inch lower than shoulder 137. The recess 140 b ofrecessed section 140 may have the same shoulder and detent. As will beexplained hereinafter, upon deformation of the central panel 102, alower edge of a portion of the restraint plate 152 may abut against theshoulder 137, while a weld affixing the restraint plate 152 to thefastening plate 150 may fit within the detent 135.

An opening, referred to herein as anchor bolt opening 144, may be formedwithin a central portion of the second recesses 138 b and 140 b. Theanchor bolt opening 144 may extend completely through the central panel102, i.e., from the second recess 138 b through to the second recess 140b. In embodiments, the anchor bolt opening 144 may generally berectangular, with a length of 4⅜ inches and a width of 3⅛ inches. Theanchor bolt opening 144 may be spaced 11/16 inches from edge 122, and 4¼inches from the bottom of the central panel 102. These dimensions areset forth by way of example, and may vary proportionately ordisproportionately with respect to each other in further embodiments.

A bore, referred to herein as anchor bolt bore 146 may extend from thebottom edge 124 of the central panel 102 up into the anchor bolt opening144. The anchor bolt bore 146 may have a diameter of 1.125 inches, butthis diameter may vary in further embodiments.

FIGS. 6 and 7 show detail of recessed sections 138, 140, anchor boltopening 144 and anchor bolt bore 146 in at a first side of panel 102adjacent edge 122. It is understood that recessed sections 134 and 136may similarly each include first and second recesses having the samecorresponding dimensions and positions relative to edge 120 and thebottom edge 124 of the central panel 102. A second anchor bolt opening144 and a second anchor bolt bore 146 may also be provided adjacent edge120 as described above with respect to FIGS. 6 and 7.

Side plate assemblies 104, 106, 108 and 110 fit within respectiverecessed sections 134, 136, 138 and 140 formed in the front and rearplanar surfaces 116, 118 of central panel 102. FIGS. 8-11 show front,rear, edge and exploded perspective views, respectively, of side plateassembly 108 which gets mounted in recess 138 in front planar surface116. Side plate assembly 108 may include a fastening plate 150 and arestraint plate 152 mounted or otherwise formed on a rear surface of thefastening plate 150 as shown in FIGS. 9-11. The side plate assembliesmay also be referred to herein as simply side plates. The fasteningplate 150 includes a number of fastening holes 156 for receivingfasteners 158 (FIG. 11) such as for example screws and/or nails. Usingthe fasteners 158 within holes 156 in fastening plate 150, the sideplate assembly 108 may be affixed to the central panel 102 withinrecessed section 138. The pattern and number of fastening holes 156 mayvary in different embodiments, but in general are sufficient to preventseparation of side plate 108 from the central panel 102 under loadsexperienced by shearwall 100. It is understood that the plates 104, 106,108 and/or 110 may be bonded to the front and rear surfaces of thecentral panel 102 by methods other than fasteners 158 and fasteningholes 156.

The fastening plate 150 may be generally rectangular and have a lengthand width as large as the length and width of the first recess 138 a.The fastening plate 150 may have shapes other than rectangular, and mayhave a length and/or width smaller than the length or width of the firstrecess 138 a in further embodiments. The fastening plate 150 may have athickness equal to the thickness of the first recess 138 a so that, onceaffixed to central panel 102, the side plate assembly 108 may be flushwith front planar surface 116. The fastening plate 150 may be thinner orthicker than the first recess 138 a in further embodiments. Furtherembodiments may not have a recess for fastening plate 150. Fasteningplate 150 may be formed of a metal, such as for example 10 gauge steel.

In embodiments the restraint plate 152 may be affixed, as by welding orbonding, onto a rear surface of the fastening plate 150. In furtherembodiments, the restraint plate 152 may be integrally formed with thefastening plate 150, such as for example where the side plate assembly108 is cast from a mold. The restraint plate 152 is positioned on a rearsurface of the fastening plate 150 such that the restraint plate 152fits within the second, deeper recess 138 b when the fastening plate 150is fastened within recess 138 a. In embodiments, the length and width ofthe restraint plate 152 are smaller than the length and width of thesecond recess 138 b, and the thickness of the restraint plate 152 isless than the depth of the second recess 138 b. Thus, when positioned inthe second recess 138 b, the restraint plate 152 does not contact sidesor bottom of the second recess 138 b. In one embodiment, the restraintplate 152 may have a length of 6½ inches, a width of 4½ inches and adepth of ½ inches. These dimensions may vary in further embodiments.Where the restraint plate 152 is welded onto fastening plate 150, theweld 161 may be spaced away from the edge 122 as shown for example inFIG. 9. When the central panel 102 deforms as explained below, the weld161 may fit within detent 135 (FIG. 7) to allow good contact (parallelsurfaces) between edges of the restraint plate 152 and the shoulder 137of the central panel 102 within the second recess 138 b.

As noted above, the side plate assembly 108 may include an openingthrough the fastening plate 150 and through the restraint plate 152. Asseen for example in FIG. 12, the opening 160 may be generallyrectangular with a chamfer 162 in one corner. In embodiments, theopening 160 may have a length of 4 inches and a width of 3⅛ inches. Inembodiments, the chamfer 162 may shorten the length of one side of theopening 160 by 3¼ of an inch so that the length of the one side is 3¼inches, and may shorten a width of one side of the opening 160 by ½ ofan inch so that the width of the one side is 2⅝ inches. The size of theopening 160 and chamfer 162 may vary in further embodiments. The chamfer162 defines a lower surface 164 inside the opening 160 for supporting abearing plate washer as explained below.

FIGS. 8-12 show an example of side plate assembly 108 provided at oneside (i.e., the right side from the front view of FIG. 2) of the frontplanar surface 116. The side plate assembly 106 may be identical to theside plate assembly 108 at an opposed side (i.e., the right side fromthe rear view of FIG. 3) of the rear planar surface 118. The side plateassemblies 104 and 110 may be the mirror images of side plate assemblies108 and 106. FIGS. 13-17 illustrate an example of side plate assembly104 provided at the other side (i.e., the left side from the front viewof FIG. 2) of the front planar surface 116. The side plate assembly 110may be identical to side plate assembly 104 at a side (i.e., the leftside from the rear view of FIG. 3) of the rear planar surface 118.

FIGS. 18 and 19 are perspective and edge views, respectively, of a pairof side plate assemblies (e.g., assemblies 108 and 110) affixed to theopposite surfaces 116, 118 of the central panel 102. As shown, thefastening plate 150 lies in contact with the central panel 102 withinthe first recess 138 a. The restraint plate 152 fits within the secondrecess 138 b, spaced from contact with the central panel 102. FIG. 18also shows a bearing plate washer 168, which extends through theopenings 160 in the side plate assemblies 108 and 110, and through theanchor bolt opening 144 in the central panel 102.

FIG. 20 is an exploded perspective view showing additional detail of howthe bearing plate washer 168 cooperates with an anchor bolt 170 tosecure the shearwall 100 to a foundation 175. As noted, the bearingplate washer 168 (on both sides of the central panel 102) extendsthrough the openings 160 in the pairs of side plate assemblies, andthrough the anchor bolt opening 144 in the central panel 102. Thebearing plate washers 168 rest on bottom surfaces 164 of thecorresponding pairs of openings 160. The bearing plate washers 168 areformed of steel and, as shown in FIG. 21, may be rectangular with alength, width and thickness of 3½ inches, 2½ inches, and 1 inch,respectively. Each of these dimensions may vary in further embodiments.Each bearing plate washer 168 may further include an anchor bolt holehaving a diameter of 1.125 inches, though the hole may be larger orsmaller than that in further embodiments.

An anchor bolt 170 is fit through each of the two anchor bolt bores 146,in the bottom surface of central panel 102, which extends up into theanchor bolt openings 144 and through the bearing plate washers 168. Theanchor bolts 170 may be affixed to bearing plates washers 168 by a pairof nuts 172 as shown for example in the perspective view of FIG. 22.

The anchor bolts 170 extend down beyond the bottom edge of shearwall100, where they may be anchored into the concrete foundation or othersupport surface. A second pair of nuts 174 (FIG. 22) may be provided onthe anchor bolts 170 to fix a height of the anchor bolts within theanchor bolt openings 144. It is a feature of the present technology thatthe plurality of side plates, and shearwall in general, may be engagedby tightening the nuts 172 within the anchor bolt openings 144 to removeany slack within the shearwall 100. In particular, by tightening thenuts 172, the bearing plate washers 168 pull down on the respectivepairs of side plate assemblies 104, 106 and 108, 110, which in turn pullthe central panel 102 against the second set of nuts 174 on anchor bolts170. Without such tightening of the nuts 172, slack may exist in theshearwall 100 at various locations and due to various manufacturingtolerances. For example, there may be slack (i.e., loose fit ormisalignment) of the fasteners 158 within fastening holes 156.Tightening the nuts 172 removes any such slack to engage the pluralityof side plates and shearwall.

It has been found that tightening of the nuts 172 and removing slackwithin the shearwall 100 enhances the initial stiffness of the shearwalland increases the magnitude of lateral force that the shearwall maytransmit at a given lateral displacement threshold. Embodiments of thepresent technology may require that the nut 172 be tightened to a leveldefined as finger-tight plus one-half turn. This level of tightening mayvary in further embodiments.

As noted with respect to FIG. 1, a bottom plate 112 may be provided on abottom edge 124 of the central panel 102. Further details of bottomplate 112 are shown in the exploded perspective view of FIG. 23 and theedge and top views of FIGS. 24 and 25. Bottom plate 112 may be formedfor example of 10 gauge steel and may extend across the entire lengthand width of bottom edge 124. Bottom plate 112 may include a pair offastening tabs 178 at the front and rear edges of bottom plate 112 whichmay include fastening holes 181 for receiving fasteners (not shown) suchas screws and/or nails for fixing the bottom plate 112 to the centralpanel 102. As shown in the views of FIGS. 23 and 25, the plate mayinclude openings 184 through which anchor bolts 170 extend. As noted,nuts 174 may be provided over the anchor bolts in contact with a lowersurface of the bottom plate 112. Bottom plate 112 may be effective inresisting overturning compressive forces exerted at the bottom cornersof the central panel 102, as well as providing an impervious moisturebarrier between the central panel 102 and the foundational supportingsurface on which shearwall 100 is mounted.

The shearwall 100 as described above provides a high degree of initialstiffness and strength to transmit forces, and ductility to dissipateenergy on constructions that may occur during natural phenomena such asseismic activity, high winds, floods and snow loads.

Additionally, it is a feature of the present technology to predictablycontrol how and where the shearwall yields upon shear loads abovethreshold levels. In particular, as mentioned above for example withrespect to FIG. 7, each pair of second, deeper recesses (e.g., 138 b and140 b) in opposed lower corners of the central panel 102 together definea narrower width section and panel 102 extending to the edges 120, 122.These two narrower width sections at opposed lower corners of shearwall100 are referred to herein as structural fuse elements 180, shown in oneside for example in FIGS. 7, 18 and 19. In accordance with aspects ofthe present technology, each fuse element 180 (also referred to hereinsimply as fuse 180) provides a controlled location at opposite sides ofpanel 102 for yielding of the shear wall 100 at shear forces above somethreshold. When applied lateral shear forces exert stresses on theshearwall above threshold levels, one side of the shearwall will yield,or buckle or fracture, in compression or tension, at the fuse 180. Inparticular, the fuse 180 will not bear as high an axial load as otherportions of the shearwall along edges 120 and 122 and yielding thereforetakes place at the fuses 180 as opposed to other positions along thelength of shearwall 100. Thus, fuses 180 provide a predictable andcontrollable manner of yielding on each side of the shearwall 100.

FIGS. 26 and 27 illustrate edge views of shearwall 100 yielding, orbuckling, or fracture, along one of the edges 120, 122 at fuse 180. Itis a further feature of the present technology to provide a high degreeof ductility in shearwall 100 after initial yield. In particular, uponyielding, the central panel will fracture (at 185) as shown in FIG. 26.The fracture is shown as being generally horizontal between planarsurfaces 116, 118 of the panel 102, but the fracture may be morevertical in further embodiments. As noted above and as shown in FIG. 26,a space may initially exist between a bottom edge of the restraintplates 152 and the shoulder 137 of the central panel 102.

However, as buckling and/or crushing of the central panel 102 continues,the restraint plates 152 of at least one of the pairs of side plates104, 106 and 108, 110 will move into contact with the shoulder(s) 137 ofone or more recesses 138 b, 140 b, as shown in FIG. 27. At this point,compressive load is applied to the shoulder 137 of the central panel102, providing residual strength to the shearwall 100 after initialyield, and only a marginal reduction in lateral-force-resisting capacityby shearwall 100 is observed as displacement levels increase. This isdue to the inherent ductility associated with direct bearing of therestraint plates 152 against the fractured central panel 102.

FIGS. 26 and 27 show the shoulder 137 at the edge 122 of the panel 102,and the weld 161 which does not extend to the edge 122. See, forexample, FIG. 9. The flat shoulder 137 provides a good bearing surfacefor the flat bottom edge of the restraint plates 152. Thus, the loadsbetween the shoulders 137 and flat bottom edge of restraint plates 152is primarily vertical. If there was a non-horizontal angle of contactbetween the bottom edge of the restraint plates and shoulders 137, thismay create horizontal forces which may force the restraint plates towedge outward to slip off shoulders 137. As noted above, the welds 161fit within detents 135 (FIG. 7) to prevent such horizontal forces fromthe welds 161.

It is another feature of the shearwall 100 that it may be constructedwith a minimum of welded parts, which can be a source of yielding andfracture under high loads. Aside from a weld affixing the restraintplate 152 to the fastening plate 150, the shearwall 100 may befabricated without welding. As noted above, in embodiments where theside plates are cast or structurally bonded, even the weld of therestraint plate 152 to fastening plate 150 may be omitted.

FIG. 28 illustrates an exploded perspective view of a top plate 182 forconnecting the upper edge 126 of shearwall 100 to the structural framing186, 188 or other support surface above shearwall 100. The top plate maymount to an outside face of the shearwall 100, in a routed recess 187.The top plate 182 may include a number of fastening holes 190 forreceiving fasteners 192 such as for example screws and/or nails. Thefastening holes 190 and fasteners 192 may be used to affix the shearwall100 to the top plate 182, and the top plate 182 to the structuralframing 186, 188. As shown in FIGS. 28-30, the top plate 182 includesgenerally planar sections 182 a and 182 c parallel to surfaces of thestructural framing and shearwall, and an angled section 182 b, betweenand connecting the planar sections 182 a and 182 c. As seen in FIGS.28-29, the planar section 182 a may be slightly longer than angledsection 182 b and planar section 182 c, though it need not be in furtherembodiments. The angled section 182 b is provided at an oblique angle tosurfaces of the structural framing 186, 188. As seen in FIG. 28, somefasteners 192 may be inserted perpendicularly to planar sections 182 aand 182 c, into the structural framing and top section of the centralpanel 102. Other fasteners 192 may be inserted perpendicularly to angledsection 182 c, and up into the structural framing 186, 188 at an angle.These fasteners 192 at an angle provide additional support for theshearwall 100 respect to the structural framing 186, 188.

In embodiments described above, side plate assemblies 104, 106, 108 and110 are substantially rectangular, and fit into substantiallyrectangular recessed sections 134, 136, 138 and 140 formed in the frontand rear planar surfaces 116, 118 of central panel 102. It is understoodthat the side plate assemblies and recessed sections may have othershapes in further embodiments. One such further embodiment is shown inFIGS. 31-32, illustrating perspective views of the front planar surface116 and rear planar surface 118, respectively, of shearwall 100. In thisembodiment, each of the plate assemblies 104, 106, 108 and 110 may haveone or more rounded edges at interior corners of the plate assemblies104, 106, 108 and 110 (i.e., the corners spaced from edges 120, 122).The radius of curvature of the rounded edges may for example be 4inches, though the radius may be larger or smaller than that in furtherembodiments.

As further seen in FIGS. 31-32, the recessed sections 134, 136, 138 and140 formed in the front and rear planar surfaces 116, 118 of centralpanel 102 may also have corresponding rounded edges to receive the plateassemblies 104, 106, 108 and 110. Rounding the corners as shown in FIG.31 reduces the required time for routing the panel 102 to form therecessed sections 134, 136, 138 and 140 as the rounding enables therecesses to be formed in a single pass at each recess plate locationwith a large-diameter cutting tool. This feature may also alleviatematerial splintering near the bottom face of the panel 102.

In summary, in one example, the present technology relates to ashearwall for use in constructions, the shearwall comprising: a centralpanel comprising first and second surfaces; a plurality of side platesconfigured to be connected to the central panel at lower corners of thefirst and second surfaces, the side plates further configured to becoupled to a support surface on which the shearwall is mounted; whereinthe central panel comprises a fuse, the fuse being a reduced areasection of the central panel between the first and second surfaces, theshearwall configured to yield at the fuse.

In another example, the present technology relates to a shearwall foruse in constructions, the shearwall comprising: a central panelcomprising first and second surfaces and a section having a reduced areabetween the first and second surfaces; a plurality of side platesconfigured to be connected to the central panel at lower corners of thefirst and second surfaces, the side plates further configured to becoupled to a support surface on which the shearwall is mounted, theplurality of side plates comprising restraint plates, the restraintplates positioned within the section of the central panel having areduced area and the restraint plates configured to inhibit buckling orfracture of the central panel after initial buckling of the centralpanel.

In a further example, the present technology relates to a shearwall foruse in constructions, the shearwall comprising: a central panelcomprising first and second surfaces, and a section having a reducedthickness between the first and second surfaces; a plurality of sideplates comprising: fastening plates for fastening the side plates to thecentral panel, and restraint plates on the fastening plates, therestraint plates of first and second side plates fitting within thesection of the central panel having a reduced area; wherein the sectionin the central panel of reduced area provides a predictable location ofyielding of the shearwall; and wherein the restraint plates provideductility after initial yielding of the shear wall by opposing yieldingof the central panel after initial yielding of the shearwall.

The foregoing detailed description of the invention has been presentedfor purposes of illustration and description. It is not intended to beexhaustive or to limit the invention to the precise form disclosed. Manymodifications and variations are possible in light of the aboveteaching. The described embodiments were chosen in order to best explainthe principles of the invention and its practical application to therebyenable others skilled in the art to best utilize the invention invarious embodiments and with various modifications as are suited to theparticular use contemplated. It is intended that the scope of theinvention be defined by the claims appended hereto.

What is claimed is:
 1. A shearwall for use in constructions, theshearwall comprising: a central panel comprising first and secondsurfaces and a section having a reduced area between the first andsecond surfaces; a plurality of side plates configured to be connectedto the central panel at lower corners of the first and second surfaces,the side plates further configured to be coupled to a support surface onwhich the shearwall is mounted, the plurality of side plates comprisingrestraint plates, the restraint plates positioned within the section ofthe central panel having a reduced area and the restraint platesconfigured to inhibit buckling of the central panel after initialbuckling of the central panel.
 2. The shearwall of claim 1, wherein thecentral panel is formed of at least one of natural wood and engineeredwood.
 3. The shearwall of claim 1, wherein the side plates are formed ofsteel.
 4. The shearwall of claim 1, wherein the side plates furthercomprise fastening plates for fastening the side plates to the centralpanel.
 5. The shearwall of claim 4, wherein the restraint plate iswelded or structurally bonded to the fastening plate.
 6. The shearwallof claim 1, wherein the side plates are coupled to the support surfaceby an anchor rod extending into the support surface at a first end, andcoupled to the side plates at a second end opposite the first end. 7.The shearwall of claim 6, wherein the plurality of side plates inengaged by tightening of the nut to remove slack in the shearwall. 8.The shearwall of claim 1, wherein first and second side plates of theplurality of side plates are aligned with each other at corners of thefirst and second surfaces of the central panel, the first side plateincluding a first opening, the second side plate including a secondopening, and the central panel including a third opening extendingbetween the first and second surfaces, the first, second and thirdopenings aligned with each other.
 9. The shearwall of claim 8, furthercomprising an anchor rod extending into the support surface at a firstend, and extending into the third opening at a second end opposite thefirst end.
 10. The shearwall of claim 9, further comprising a bearingwasher plate supported on edges of the first and second openings of thefirst and second side plates, the anchor rod extending through a hole inthe bearing washer plate and affixed to the bearing washer plate by anut.
 11. The shearwall of claim 9, wherein the nut is tightened toengage the plurality of side plates and to remove slack in theshearwall.
 12. The shearwall of claim 8, wherein the third opening isformed in the reduced area section of the central panel.
 13. A shearwallfor use in constructions, the shearwall comprising: a central panelcomprising first and second surfaces, and a section having a reducedthickness between the first and second surfaces; a plurality of sideplates comprising: fastening plates for fastening the side plates to thecentral panel, and restraint plates on the fastening plates, therestraint plates of first and second side plates fitting within thesection of the central panel having a reduced area; wherein the sectionin the central panel of reduced area provides a predictable location ofyielding of the shearwall; and wherein the restraint plates provideductility after initial yielding of the shear wall by opposing yieldingof the central panel after initial yielding of the shearwall.
 14. Theshearwall of claim 13, wherein the central panel is formed of at leastone of natural wood and engineered wood.
 15. The shearwall of claim 13,wherein the first and second side plates are aligned with each other atcorners of the first and second surfaces of the central panel, theshearwall further comprising an opening through the first and secondside plates and central panel.
 16. The shearwall of claim 15, furthercomprising an anchor rod extending into the support surface at a firstend, and extending into the opening at a second end opposite the firstend.
 17. The shearwall of claim 16, further comprising a bearing washerplate supported on edges of the first and second side plates at theopening, the anchor rod extending through a hole in the bearing washerplate and affixed to the bearing washer plate by a nut.
 18. Theshearwall of claim 17, wherein the nut is tightened to engage theplurality of side plates and to remove slack in the shearwall.
 19. Ashearwall for use in constructions, the shearwall comprising: a centralpanel comprising first and second surfaces and sections having a reducedarea between the first and second surfaces; a plurality of side platesconfigured to be connected to the central panel at lower corners of thefirst and second surfaces, the side plates further configured to becoupled to a support surface on which the shearwall is mounted, theplurality of side plates comprising restraint plates, the restraintplates positioned within the sections of the central panel having areduced area and the restraint plates configured to transfer loads onthe central panel to the support surface.
 20. The shearwall of claim 19,wherein the central panel is formed of at least one of natural wood andengineered wood.
 21. The shearwall of claim 19, wherein the side platesare formed of steel.